Shock-proof nylon carpet system

ABSTRACT

A SHOCK-PROOF CARPET SYSTEM HAVING A FACE YARN OF TEXTURED NYLON CONTAINING UP TO ABOUT TWELVE WEIGHT PERCENT OF AN INTERNAL ADDITIVE SELECTED FROM ETHYLENE OXIDE CONDENSATION PRODUCTS, A PRIMARY BACKING OF JUTE OR SPUNBONDED SYNTHETIC MATERIAL, A TUFT-LOCKING LATEX MADE ELECTRICALLY CONDUCTIVE BY THE ADDITIVE OF UP TO ABOUT TEN WEIGHT PERCENT OF AN ANTISTATIV MATERIAL, AND A STANDARD SECONDARY BACKING.

United States Patent 3,834,977 SHOCK-PROOF NYLON CARPET SYSTEM RonaldEdward Rothwell, Colonial Heights, Va., Cipriano Cipriani, Morristown,N.J., and Julian Lee Rush, Richmond, Va., assignors to Allied ChemicalCorporation,

New York, N.Y.

No Drawing. Filed Mar. 29, 1972, Ser. No. 239,378

Int. Cl. D03d 27/00 US. Cl. 161-67 8 Claims ABSTRACT OF THE DISCLOSURE Ashock-proof carpet system having a face yarn of textured nyloncontaining up to about twelve weight percent of an internal additiveselected from ethylene oxide condensation products, a primary backing ofjute or spunbonded synthetic material, a tuft-locking latex madeelectrically conductive by the additive of up to about ten weightpercent of an antistatic material, and a standard secondary backing.

CROSS REFERENCE TO RELATED APPLICATION This application is related tocopending application, Ser. No. 185,816, filed Oct. 1, 1971, by LambertoCrescentini and Gene Clyde Weedon, now abandoned, in favor ofcontinuation-in-part Ser. No. 239,905, filed Mar. 31, 1972, which wasabandoned in favor of continuationin-part Ser. No. 274,971, filed Oct.11, 1972, and is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION This invention relates to a shock-proofcarpet system based on nylon. More particularly it relates to animproved carpet system based on nylon made shock-proof by use of certainadditives. And, still more particularly it relates to a carpet systembased on nylon made shockproof by use of additives that actually improveits shockproofness as the carpet system Wears.

Carpet systems are well known to generate considerable charges of staticelectricity when a person in contact therewith traverses the carpetsystems fibrous layer. Such charges are quite naturally transferred tothe person traversing said carpet system and upon grounding, the chargesare discharged causing momentary shock and a source of considerableirritation. And, although several carpet systems have been devised in aneffort to improve this system, all tend to become less and less viablewith use. One such static-discharging floor covering system is disclosedin U.S. Pat. 2,302,003 wherein a coating of a flexible electricallycoating material, such as a rubber compound containing carbon black, isaflixed to the under side of a rug, and a plurality of electricallyconducting elements, such as cotton cords, and an electricallyconductive rubber composition are used which come into contact with thecoating and thus extend to substantially the top of the rug. Anothermore recent approach to solving this problem of static charge buildup ina carpet system is described in U.S. Pat. 3,288,175, wherein up to about10% by weight on a continuous carpet system 'is comprised of metallicrfibers in continuous metal to metal contact that have the functionaland aesthetic properties of nonmetallic textiles yet possess metallicelectrical conductivity thus dissipitating the normal static chargebuildup. Still another approach to the solution of this static buildupproblem is described in US. Pat.

A prime object of this invention is to provide a shock- -proof carpetsystem. Another object of this invention is to provide a shock-proofnylon carpet system. A further object of this invention is to provide ashock-proof nylon carpet system wherein the additives utilized in makingsuch carpet system are maintained in the carpet system throughout thelife of the carpet system. A still further object of this invention isto provide a shock-proof nylon carpet system wherein the staticelectricity buildup is lower than the threshold of sensitivity tohumans. And, a still further object of this invention is to provide ashock-proof nylon carpet system wherein the static electricity buildupgets actually lower or improves its shock proof effectiveness withnormal use. Other objects will appear hereinafter as the description ofthe invention proceeds.

The above and other objects of this invention are accomplished inpreparing an antistatic textile article comprising a fibrous textilelayer of the pile type, said pile being prepared from a polyamide fibercontaining between about 1% and about 12% by Weight of a predominantlybranched, chain-extended polymer of the reaction product of a compoundrepresented by the formula:

where a, b, c, d, w, x, y, and z are each a whole number and R is adifunctional radical from a hydrocarbon containing 1 to 13 carbon atoms,and at least one compound selected from the group consisting ofdiepoxides and compounds which yield the following divalent radicals:

O O O O where R is a difunctional radical derived from aromatic,heterocyclic, cycloaliphatic or aliphatic hydrocarbons or combinationsof them having said fibrous pile secured to a primary backing, and anadhesive conductive latex backing added thereto. The adhesive conductivelatex is made conductive by containing up to ten Weight percent of saidlatex from a compound selected from the group consisting of the reactionproduct of a compound represented by the formula:

where a, b, c, d, w, x, y, and z are each a whole number and R is adifunctional radical from a hydrocarbon containing 1 to 13 carbon atoms,and at least one compound selected from the group consisting ofdiepoxides and compounds which yield the following divalent radicals:

where R is a difunctional radical derived from aromatic, heterocyclic,cycloaliphatic or aliphatic hydrocarbons or combinations of them havingsaid fibrous pile secured to a primary backing, and an adhesiveconductive latex backing added thereto and polyethylene oxide.

The antistatic-fiber of this invention can contain certain conventionaladditives without any adverse efiects upon the overall shock-proofcarpet system of this invention. That is, the carpet system of thisinvention is compatible in all instances with other additives, naturallyeither necessary or desirable, such as, dyeing assists and colorants,stabilizers, antioxidants and delustrants among others.

Surprisingly, such improved shock-proof carpet system of this inventionnot only provides a shock-proof carpet system initially below thethreshold of sensitivity to humans, but actually improves itsshock-proof efiectiveness with use. Such threshold of sensitivity tohumans has been established at between approximately about 2500 to about4000 volts. See Modern Textiles, April 1971 publication, article AShock-Free Carpet System At 10% Relative Humidity and papers of theAmerican Association For Textile Technology, Inc. by D. H. Martin, R. D.Radford and K. R. Lea. Another static test procedure for textiles isdescribed in technical bulletin No. 2-015, dated 3/1/70 by BrunswickCorporation, Technical Products Div., 69 W. Washington St., Chicago, 11160602. These publications also illustrate the walk-test method employedin static electricity buildup evaluation. These test methods aresomewhat redundant, but do complement each other to a great extent. Theydo agree that a static level greater than about 3 kilovolts or 3000volts, as measured by these tests, will produce a shock detectable bymost people and objectionable to some.

The principles of practicing the invention are further illustrated bythe following examples, but without limiting the invention to thedetails thereof.

Example 1 Polycaproamide polymer is used having a moisture content of0.05% to 0.10%, total constituents extractable by hot water of 1% to 2%,and formic acid relative viscosity of 62. The polymer contains about0.2% titanium dioxide dulling agent, antioxidant, and 6% of anantistatic agent consisting of a polyether of dimethylterephthalate andTetronic 1504 supplied by Wyandotte and covered under US. Pat. 2,979,528by Lunsted. The Tetronic 1504 is one of man ytetrol compoundscommercially available as tetronic series block copolymers havingmolecular weights between 1650 and 26,000. This series varies in lengthof poly(oxyethylene) chain and poly(oxypropylene) chain. -A 3 and 4digit code number indicates the molecular composition. When four digitsare employed, the first two explain the average molecular weight of thehydrophobe (poly(oxypropylene) branches on the alkylenediamine). Whenthree digits are used only the first number serves this purpose. Thelast digit of each code number represents the weight percentage ofhydrophilic (poly(oxyethylene) units to the nearest 10% The antistaticmaterial is metered at the hopper with the polycaproamide polymer andboth are fed into a screw extruder havin gan exit temperature of 260 C.The polymer is forwarded at a pressure of 1900 p.s.i.g. through a sandfilter to a spinnerette plate with 70 holes, each of which is 0.95 inchdeep and 0.025 inch in diameter. The freshly extruded filaments descenda spinning tower into which is air conditioned at 70 F. and 65% relativehumidity is admitted. The yarn emerging from the spinning tower contactsa ceramic roll which applies a lubricant finish, and the yarn then iswound onto a package at 1850 feet per minute. The yarn thus obtained hasa denier of 3150, is drawn over a /8 inch diameter draw pin at adelivery rate of 1536 feet per minute which is 3.01 times the feed ratein order to obtain a dra'wn yarn denier of 1050 denier. Each of the '70filaments has a .denier of 15. During drawing the yarn is passed 5 wrapstrolled at 20% are compared in Table I with control carpets.

TABLE I Walk testmaximnm voltage generated (KV) After Aft-er 20M 40MSample Initial treads treads Control carpet (regular yarn-regular latex)14. 4 Carpet vw'th internal antistatyarn as defined in this invention 5.8 5. 7 5. 6 Carpet with internal antistat yarn as defined in thisinvention in combination with latex containing five weight percentpolyethylene oxide antistatic material 2. 3 2. 3 2. 3 Carpet withinternal antistat yarn as defined in this invention in combination withlatex containing five weight percent of the internal antistat used inthe yarn 2. 2 2. 2 2. 2

Example 2 As in Example 1, except that the 6% antistatic agentcontaining an antioxidant is added by injection at the point where themolten polymer is extruded from the reactor prior to pelletizing. Thesubsequent Washing cycles to extract any unreacted lactam and oligomersfrom the pellets did not effect the concentration of the antistat in thepolymer as the antistat is insoluble in water. After washing and drying,the polymer was processed as in Example 1. The maximum voltage generatedin RV in the Walk Test is 2.4 initially. It shows 2.2 after 20M treadsand 2.0 after 40M treads.

Example 3 As in Example 1, except that 400 ends of undrawn yarn arecombined into a tow. The tow is drawn, crimped and cut into 6.5 inchlong staple, all in a continuous operation. The staple is then spun intoa 2.25 with 3.5 Z twist and converted into 40 ounces/yd. cut pile plushtype carpets. The maximum voltage generated in KV in the Walk Test is2.3. After 20M treads it dropped to 2.2 and after 40M treads it droppedto 2.01.

Example 4 As in Example 1, except that nylon 6,6 polymer is used.Continuous and staple yarns are prepared and the results in the carpetswere as follows: initial KV is 2.9; after 20M treads, 2.1 KV; and after40M treads the KV is 1.5.

Example 5 As in Example 1, except the yarn internal antistatic additiveis added in an amount of 10 weight percent of the polymer. The resultingmaximum voltage in the carpet is equivalent to results in Table I.

Example 6 As in Example 1, except the yarn internal antistatic additiveis also used in the conductive latex. The resulting maximum voltage inthe carpet is equivalent to results in Table I.

It is to be understood that although the instant invention has beendescribed as set forth herein in a preferred form, obviously numerousmodifications can be made without parting from the scope and spiritthereof, and such modifications are to be understood as coming withinthe scope of the appended claims.

We claim:

1. In a textile article comprised of an antistatic polyamide fiber abacking having said fiber secured thereto, and

a coating on said backing contacting said fiber, said coating containingan additive to reduce buildup of static electricity the improvementconsisting essentially of using for said additive to reduce buildup ofstatic electricity in said polyamide fiber between about 1 percent andabout 12 percent by weight of a predominantly branched chainextendedcompound represented by the formula where a, b, c, d, w, x, y, and z areeach a whole number and R is a difunctional radical from a hydrocarboncontaining 1 to 13 carbon atoms, and at least one compound selected fromthe group consisting of diepoxides and compounds which yield thefollowing divalent radicals:

O O O O JLR'Jl, and l1 l R' 1L ll where R is a difunctional radicalderived from aromatic, heterocyclic, cycloaliphatic or aliphatichydrocarbons or combinations of them whereby said textile article willgenerate less than 3 kilovolts of static electricity by the walk testand the static electricity buildup gets lower with normal use of saidtextile article.

2. The article of claim 1 wherein the primary backing is made ofsynthetic material or jute.

3. The article of claim '1 wherein a secondary backing is added to saidconductive latex backing, said secondary backing is made up ofspun-bonded or woven polypropyl material or jute.

I 4. The article of claim 1 wherein the polyamide is selected from thegroup consisting of polycaproamide and polyhexamethylene adipamide.

5. The article of claim 1 wherein the latex backing is styrene butadienerubber latex.

6. The article of claim 5 wherein the latex contains up to ten weightpercent of said latex of a compound selected from the group consistingof the reaction product of a compound as defined in claim 1 andpolyethylenk oxide.

7. The article of claim 6 wherein the antistatic efiicacy improves withnormal use.

8. The article of claim 1 wherein said additive to said coating is thesame additive as is in said polyamide fiber.

References Cited UNITED STATES PATENTS 3,554,824 1/1971 Callahan 156723,658,744 4/1972 Brindell et a1. 161-62 3,510,386 5/1970 Goins et a1.16167 3,719,547 3/1973 Martin et a1. 161'67 HAROLD ANSHER, PrimaryExaminer J. I. BELL, Assistant Examiner U .8. Cl. X.R. l6162

